Merge tag 'v4.18' into rdma.git for-next

Resolve merge conflicts from the -rc cycle against the rdma.git tree:

Conflicts:
 drivers/infiniband/core/uverbs_cmd.c
  - New ifs added to ib_uverbs_ex_create_flow in -rc and for-next
  - Merge removal of file->ucontext in for-next with new code in -rc
 drivers/infiniband/core/uverbs_main.c
  - for-next removed code from ib_uverbs_write() that was modified
    in for-rc

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 29 insertions, 14 deletions

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 8d85046adcc8..9670e70139fd 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -29,6 +29,7 @@
 #include <linux/kallsyms.h>
 #include <linux/random.h>
 #include <linux/prctl.h>
+#include <linux/nmi.h>
 
 #include <asm/asm.h>
 #include <asm/bootinfo.h>
@@ -655,28 +656,42 @@ unsigned long arch_align_stack(unsigned long sp)
 	return sp & ALMASK;
 }
 
-static void arch_dump_stack(void *info)
+static DEFINE_PER_CPU(call_single_data_t, backtrace_csd);
+static struct cpumask backtrace_csd_busy;
+
+static void handle_backtrace(void *info)
 {
-	struct pt_regs *regs;
+	nmi_cpu_backtrace(get_irq_regs());
+	cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy);
+}
 
-	regs = get_irq_regs();
+static void raise_backtrace(cpumask_t *mask)
+{
+	call_single_data_t *csd;
+	int cpu;
 
-	if (regs)
-		show_regs(regs);
+	for_each_cpu(cpu, mask) {
+		/*
+		 * If we previously sent an IPI to the target CPU & it hasn't
+		 * cleared its bit in the busy cpumask then it didn't handle
+		 * our previous IPI & it's not safe for us to reuse the
+		 * call_single_data_t.
+		 */
+		if (cpumask_test_and_set_cpu(cpu, &backtrace_csd_busy)) {
+			pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n",
+				cpu);
+			continue;
+		}
 
-	dump_stack();
+		csd = &per_cpu(backtrace_csd, cpu);
+		csd->func = handle_backtrace;
+		smp_call_function_single_async(cpu, csd);
+	}
 }
 
 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
 {
-	long this_cpu = get_cpu();
-
-	if (cpumask_test_cpu(this_cpu, mask) && !exclude_self)
-		dump_stack();
-
-	smp_call_function_many(mask, arch_dump_stack, NULL, 1);
-
-	put_cpu();
+	nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace);
 }
 
 int mips_get_process_fp_mode(struct task_struct *task)